酯醚型聚羧酸减水剂对硫铝酸盐水泥性能的影响

Effects of ester ether copolymer PCE on the properties of CSA

采用自由基聚合法合成了酯醚型聚羧酸减水剂(PCE)。红外光谱分析表明,该减水剂分子结构中同时含有酯型与醚型支链。在此基础上,研究了酯醚型PCE对硫铝酸盐水泥(CSA)性能及水化微观形貌的影响。结果表明,随着酯醚型PCE掺量的增加,CSA的标准稠度用水量逐渐减少,凝结时间延长,浆体流动度增大。与未掺PCE时相比,当酯醚型PCE掺量为0.6%时,标准稠度用水量减少38%,初、终凝时间分别延长15%、19%,浆体流动度达到最大值,CSA浆体流动度1 h经时损失率31%,2 h经时损失率为67%。由于酯醚型PCE对CSA浆体的缓凝作用,使CSA浆体中AFt晶体生长更均匀,晶体网络分布结构更密实,因此可显著提高CSA砂浆的后期强度。

The ester ether copolymer polycarboxylate superplasticizer(PCE)was synthesized via free radical copolymerization.Based on the analysis by infrared spectroscopy,the structure of ester ether copolymer PCE contains ester and ether side chains.The effects of ester ether copolymer PCE on the properties and hydration morphology of sulphoaluminate cement(CSA)were systematically investigated.The results show that with the increase of ester ether copolymer PCE,the water consumption of CSA standard consistency decreases gradually,the setting time prolongs gradually,and the fluidity increases gradually.When the content of ester ether copolymer PCE increased to 0.6%,the water consumption of standard consistency decreased by 38%,the initial setting time was prolonged by 15%,the final setting time was prolonged by 19%,and the fluidity reached the maximum.The fluidity evolution loss was only 31% at 1 h and 67% at 2 h.Due to the retarding effect of ester ether copolymer PCE on CSA slurry,the early mechanical strength of CSA develops slowly,but the hydration product AFt crystal in CSA slurry grows and develops better,with more uniform crystal distribution,more dense network structure,and obviously improved mechanical strength of CSA mortar in the later stage.